A blade, like a blade of a wind turbine, is exposed to numerous environmental influences like ultraviolet light, rain, ice, hail and abrasion, which is originated by micro-particles in the wind passing by. Even the wind, which is acting on the blade, causes mechanic loads at the blade.
The blade, especially the surface of the blade, has to withstand the impacts—thus the surface of the blade is treated and processed accordingly.
It is known to use a painting at the surface to deal with the impacts addressed above.
Preferably a coating is brought towards the blade-surface by help of a spray gun. The spray gun can be part of an automated painting process or may even be used as hand-held in a manual handwork-process. A compressed gas like air is used to direct paint particles to the blade surface. As a result an even coating of liquid is originated at the blade-surface.
However this method shows the disadvantage that the whole painting procedure is time consuming and requires separate painting facilities with ventilation, heating, . . . etc. Thus the method is quite expensive in view to the costs.
It is also known to use a so called “gel-coat” to protect the surface of a blade, which is made of a composite material. The most common gel-coats comprise a “styrene-based” resin.
The gel-coat is liquid and is usually applied into a mould at a bottom layer. On top of the gel-coat additional layers of composite material, Balsa-wood, . . . , etc. are arranged in a sandwich-structure to build up the blade. All layers are cured together by resin, which is applied into the mould and to the layers.
As a result of this method the visible surface of the composite or blade shows a high-quality finish.
However the styrene-based gel-coat has a very bad odor and even comprises a health-risk for the personnel, who handle the gel-coat during the manufacturing of the blade. As a result additional steps for the personnel-protection are needed while even the costs are rising.